1. Field of the Invention
The present invention relates to an image transmission apparatus and method and an image transmission system, more particularly to techniques of displaying image signals transmitted from a plurality of apparatuses on the same screen of a remotely located apparatus.
2. Related Background Art
A system is being developed in which images taken with a plurality of cameras are displayed at the same time on the screen of a single monitor located remotely from the cameras, by using a picture-in-picture method or the like. Such a system is widely used for monitoring or other applications, and all image signals picked up by cameras are transmitted via wired or wireless transmission paths to the monitor. Such an image transmission system will be described with reference to FIGS. 1 and 2.
FIGS. 1 and 2 are schematic diagrams showing conventional image transmission systems. FIG. 1 shows a system using wired transmission paths, whereas FIG. 2 shows a system using wireless transmission paths.
In FIG. 1, a first camera unit 102 and a second camera unit 103 are connected via wired transmission paths 106 to a monitor unit 101.
The monitor unit 101 receives an image signal generated by the first camera unit 102 which picked up an image of an object 104, and an image signal generated by the second camera unit 103 which picked up an image of an object 105. These image signals are synthesized to display it on the same screen. In the example shown in FIG. 1, the image of the object 104 picked up with the first camera unit 102 is displayed in a main screen area of the monitor unit 101, whereas the image of the object 105 picked up with the second camera unit 103 is displayed in a partial screen area of the monitor unit 101, being superposed upon the image of the object 104. In the following, a screen area occupying 50% or more of the effective display area of the screen of the monitor unit 101 is called a main image plane, whereas the screen area not occupied by the main image plane is called a sub image plane.
In FIG. 2, a monitor unit 101, a first camera unit 102, and a second camera unit 103 each equipped with a wireless communication unit 206. The first and second camera units 102 and 103 transmit image signals from the communication units 206 to the monitor unit 101. The monitor unit 101 receives an image signal generated by the first camera unit 102 which picked up an image of an object 104, and an image signal generated by the second camera unit 103 which picked up an image of an object 105. These image signals are synthesized to display it on the same screen. In the example shown in FIG. 2, the monitor unit 101 displays the image of the subject 104 picked up with the first camera unit 102, in the main image plane, and displays the image of the subject 105 picked up with the second camera unit 103, in the sub image plane being superposed on the main image plane.
Next, the structures of the monitor unit 101, first camera unit 102 and second camera unit 103 will be described with reference to FIG. 3.
In the first camera unit 102 shown in FIG. 3, a camera unit A103 picks up an optical image of the subject 104 to generate an electrical signal of a predetermined type. A signal processing unit A302 digitizes the electrical signal supplied from the camera unit A301 to convert it into an image signal of a predetermined format. The image signal converted by the signal processing unit A302 is an image signal matching a size of an effective display area of the monitor unit 101. A transmitting unit A303 converts the image signal processed by the signal processing unit A302 into a signal having a data format suitable for wired or wireless transmission.
In the second camera unit 103, a camera unit B304 picks up an optical image of the subject 105 to generate an electrical signal of a predetermined type. A signal processing unit B305 digitizes the electrical signal supplied from the camera unit B304 to convert it into an image signal of a predetermined format. Similar to the case of the signal processing unit A302, the image signal converted by the signal processing unit B305 is an image signal matching a size of an effective display area of the monitor unit 101. A transmitting unit B306 converts the image signal processed by the signal processing unit B305 into a signal having a data format suitable for wired or wireless transmission.
In the monitor unit 101, a receiving unit 307 receives image signals transmitted from the transmitting units A303 and B306 via wired or wireless transmission paths. A signal processing unit C308 converts the image signal received by the receiving unit 307 into a signal of a type capable of being displayed on a display unit 309. Specifically, the signal processing unit C308 convert an image signal transmitted from each camera unit into an image signal matching the size and area of an image plane in which the image is displayed. The display unit 309 displays image signals transmitted from the first and second camera units 102 and 103.
As above, in order to display the image signals transmitted from a plurality of camera units 102 and 103 on the same display screen of the image transmission system shown in FIG. 1 or FIG. 2, each camera unit transmits to the monitor unit 101 an image signal matching the size of an effective display area of the monitor unit 101. The monitor unit 101 thins the image signals so as to make them match the sizes of display areas of the main and sub image planes, and synthesizes them so as to display them on the same display screen in a superposed manner.
In order to display image signals on the main and sub image planes in a superposed manner, the monitor unit 101 processes the image signals so as not to display the image signals of the main image plane superposed upon the sub image plane. However, the conventional camera unit 102 transmits all the image signals of the main image plane, including the image signals superposed upon the sub image plane, to the monitor unit 101. Since the camera unit 102 transmits the image signals not displayed on the camera unit 101, a use efficiency of a transmission path is degraded and a transmission power of the camera unit 101 is consumed wastefully.
Furthermore, the monitor unit 101 thins the image signal transmitted from the camera unit 103 so as to make it match the size of a display area of the sub image plane and thereafter the thinned image signal is synthesized with the image signal of the main image plane. However, the conventional camera unit 101 transmits the monitor unit 101 the image signal matching not the display area of the sub image plane but the effective display area of the monitor unit 101. Since the camera unit 103 transmits all the image signals including those which are thinned by the monitor unit 101, a use efficiency of a transmission path is degraded and a transmission power of the camera unit 102 is consumed wastefully.
The above disadvantages are more conspicuous for wireless transmission paths having a limited amount of transmission data, than for wired transmission paths.
An object of the present invention is to solve the above-described problems.
Another object of the invention is to provide an image transmission apparatus capable of improving a use efficiency of transmission paths and reducing a transmission power to be consumed.
As a preferred embodiment for such objects, the invention discloses an image transmitting apparatus, comprising: (a) receiving means for receiving first and second image signals transmitted from an external apparatus; (b) display means for displaying the first and second image signals on a same display screen; and (c) transmitting means for transmitting, to the external apparatus, information regarding a display area of the second image signal.
As another embodiment, the invention discloses an image transmitting apparatus, comprising: (a) receiving means for receiving first and second image signals transmitted from an external apparatus; (b) signal processing means for synthesizing the first and second image signals; and (c) transmitting means for transmitting, to the external apparatus, information regarding an area to be synthesized by the signal processing means.
As another embodiment, the invention discloses an image transmitting apparatus, comprising: (a) input means for inputting an image signal; (b) signal processing means for reducing a data amount in a predetermined area of the image signal; and (c) transmitting means for transmitting the image signal processed by the signal processing means to an external apparatus, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are displayed in an overlap manner.
As another embodiment, the invention discloses an image transmitting apparatus, comprising: (a) input means for inputting an image signal; (b) converting means for converting the image signal into an image signal having a predetermined size; and (c) transmitting means for transmitting the image signal converted by the converting means to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are displayed.
As another embodiment, the invention discloses an image transmitting apparatus, comprising: (a) input means for inputting an image signal; (b) signal processing means for reducing a data amount in a predetermined area of the image signal; and (c) transmitting means for transmitting the image signal processed by the signal processing means to an external apparatus, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention discloses an image transmitting apparatus, comprising: (a) input means for inputting an image signal; (b) converting means for converting the image signal into an image signal having a predetermined size; and (c) transmitting means for transmitting the image signal converted by the converting means to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention disclosed an image transmitting apparatus, comprising: (a) first storage means for storing a first image signal received via a transmission path; (b) second storage means for storing a second image signal received via the transmission path; and (c) synthesizing means for reading the first and second image signals stored in the first and second storage means and synthesizing the read first and second image signals, wherein the first and second image signals are signals processed so as to match a size of an area to be synthesized by the synthesizing means.
Another object of the invention is to provide an image transmission method capable of improving a use efficiency of transmission paths and reducing a transmission power to be consumed.
As a preferred embodiment for such objects, the invention discloses an image transmitting method, comprising the steps of: (a) receiving first and second image signals transmitted from an external apparatus; (b) displaying the first and second image signals on a same display screen; and (c) transmitting, to the external apparatus, information regarding a display area of the second image signal.
As another embodiment, the invention discloses an image transmitting method, comprising the steps of: (a) receiving first and second image signals transmitted from an external apparatus; (b) synthesizing the first and second image signals; and (c) transmitting, to the external apparatus, information regarding an area of the second image signal to be synthesized.
As another embodiment, the invention disclosed an image transmitting method, comprising the steps of: (a) inputting an image signal; (b) reducing a data amount in a predetermined area of the image signal; and (c) transmitting the image signal with a reduced data amount of the predetermined area, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are displayed in an overlap manner.
As another embodiment, the invention discloses an image transmitting method, comprising the steps of: (a) inputting an image signal; (b) converting the image signal into an image signal having a predetermined size; and (c) transmitting the converted image signal to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are displayed.
As another embodiment, the invention discloses an image transmitting method, comprising the steps of: (a) inputting an image signal; (b) reducing a data amount in a predetermined area of the image signal; and (c) transmitting the image signal with a reduced data amount of the predetermined area to an external apparatus, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention discloses an image transmitting method, comprising the steps of: (a) inputting an image signal; (b) converting the image signal into an image signal having a predetermined size; and (c) transmitting the converted image signal to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention discloses an image transmitting method, comprising the steps of: (a) storing a first image signal received via a transmission path in a first memory; (b) storing a second image signal received via the transmission path in a second memory; and (c) reading the first and second image signals stored in the first and second memories and synthesizing the read first and second image signals, wherein the first and second image signals are signals processed so as to match a size of an area to be synthesized.
Another object of the invention is to provide an image transmission system capable of improving a use efficiency of transmission paths and reducing a transmission power to be consumed.
As a preferred embodiment for such objects, the invention discloses an image transmitting system, comprising: (a) receiving means for receiving first and second image signals transmitted from an external apparatus; (b) display means for displaying the first and second image signals on a same display screen; and (c) transmitting means for transmitting, to the external apparatus, information regarding a display area of the second image signal.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) receiving means for receiving first and second image signals transmitted from an external apparatus; (b) signal processing means for synthesizing the first and second image signals; and (c) transmitting means for transmitting, to the external apparatus, information regarding an area to be synthesized by the signal processing means.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) input means for inputting an image signal; (b) signal processing means for reducing a data amount in a predetermined area of the image signal; and (c) transmitting means for transmitting the image signal processed by the signal processing means to an external apparatus, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are displayed in an overlap manner.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) input means for inputting an image signal; (b) converting means for converting the image signal into an image signal having a predetermined size; and (c) transmitting means for transmitting the image signal converted by the converting means to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are displayed.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) input means for inputting an image signal; (b) signal processing means for reducing a data amount in a predetermined area of the image signal; and (c) transmitting means for transmitting the image signal processed by the signal processing means to an external apparatus, wherein the predetermined area is an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) input means for inputting an image signal; (b) converting means for converting the image signal into an image signal having a predetermined size; and (c) transmitting means for transmitting the image signal converted by the converting means to an external apparatus, wherein the predetermined size is a size of an area of the external apparatus where the image signal and another image signal are synthesized.
As another embodiment, the invention discloses an image transmitting system, comprising: (a) first storage means for storing a first image signal received via a transmission path; (b) second storage means for storing a second image signal received via the transmission path; and (c) synthesizing means for reading the first and second image signals stored in the first and second storage means and synthesizing the read first and second image signals, wherein the first and second image signals are signals processed so as to match a size of an area to be synthesized by the synthesizing means.
Still other objects of the present invention, and the advantages thereof, will become fully apparent from the following detailed description of the embodiments.